Smoke indicator



May 12,1936. I 'r. w. McNElLL EIAL 2,040,265

SMOKE INDICATOR Filed March 7; 1932 2 Sheets-Sheet 1 Airy May 12, 1936. T. w. MCNEILL ET AL 2,040,265

SMOKE INDICATOR Filed March 7, 19:52 2 Sheets-Sheet 2 Patented May 12, 19.?6

UNITED STATES PATENT OFFICE 2.04am SMOKE INDICATOR Application March 7, 1932, Serial No. 597,148

12 Claims. (01. 88-14) This invention relates to indicating devices and more particularly to devices of this character for indicating the presence and density of smoke and the like.

One object of the present invention is to provide a simple and economical device for the purpose intended having a rigid and sturdy construction and capable of being installed with a minimum amount of time and efi ort.

1:) Another object is to provide an emclent form of indicating device for smoke and the like which is in the form of a unitary construction and requires connection at one side only of a smoke conduit such as the breeching or other connection 15 between a combustion chamber and smoke stack.

rangement whereby the thickness of the body of 25 smoke through which the light rays travel may be readily altered.

- Still another object is the provision of means for visually checking and calibrating the indication obtained by the indicating means.

30 A further object of the invention is to provide means associated with the light inlet and sight tubes whereby the transparent panels closing the end of the tubes will be protected from deposits of smoke and soot thereon.

35 A further object is to provide means for promptly and effectively clearing the device of smoke so that the operator may be assured that he is'obtaining a zero indication.

A still further object -of .the invention is to provide an arrangement for passing light rays through a body of smoke onto a light sensitive means whereby variations in the density of the smoke will produce variations in the condition of the light sensitive means due to the changes in intensity of the light impinging upon it.

To these and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features .being pointed out in the claims-as the end of the specification.

In the drawings: Fig. 1 is a front elevation-of the device of the present invention; v 55 Fig. 2 is a plan view;

Fig. 3 is a longitudinal section along line 3-3 of Fig. 2;

Fig. 4 is a fragmentary sectional plan view along line 4-4 of Fig. 3; I

Fig. 5 is an enlarged sectional view of one of 5 the sight tubes,- showing the ventilating apertures and the arrangement for securing the glass in the end of the tube;

Fig. 6 is a fragmentary sectional view of the tube taken substantially along lines 6-4 of Fig.

2 and showing the provision for horizontal ad justment of the tube;

Fig. 7 illustrates a modified construction of the smoke chamber; and

Fig. 8 is a modified view showing the adaptation of the invention for use with a light sensitive indicating means.

Similar reference numerals throughout the several views indicate the same parts.

The present embodiment of the invention pro vides a smoke indicating and measuring device which is particularly advantageous for use in connection with smoke conduits which are inace cessible except from one side and thus it not only performs all of the functions of smoke indicating devices heretofore in use. but at the same time materially reduces the size of equipment and the number of parts with a consequent reduction in cost both of materials and installation. 7

Referring more particularly to the drawings, numeral II indicates generallythe box or housing which constitutes the smoke trap chamber. In its preferred form the housing It is tapered but it is to be understood that the shape oi the houslnl is in general immaterial. The housing I! is preferably of metal either in sheet form or cast and is provided'with a flange H having bolt holes l2, it formed therein as a convenient means for attaching the housing to a breeching or other conduit through which the products of combus- 40 tion are conveyed between the pointof combustion of the fuel and the point of emission from the stack into the open air; For the sake of simplicity only one wall of the breaching or smoke conduit is shown and is indicated by numeral I3 in Fig. 2. The breeohing or smoke conduit has an opening therein registering with the opening M of the housing ll.

Means are provided for causing a stream of gases from the breeching to enter and pass 50. through the smoke chamber formed by the hous ing It. While this-result may be eirected in viarious manners, one expedient which has been found very satisfactory is to provide a deflecting plate I! located in cooperative relation with the This deflector is preferably, although not necessarily, secured on the housing by means of detachable securing devices, being in the present instance screws or bolts I6, I6 passing through the wall of the chamber and threaded into tapped openings in flanges I1, I! formed on the deflector. The deflector I5 is preferably formed with a portion I8 extending in a direction substantially parallel with the axis of the opening I4, and comprises another portion I9 extending out of alignment with the portion I8 so as to be biased in a direction opposed to the travel of the smoke through'the conduit.

At this point it may be pointed out that the deflector I 5 may be disposed as shown in Figs. 2 and 4 or may be reversed by merely inverting it and securing it in such position. Thus the device may be secured in an operative manner on either side of the conduit by merely inverting the deflector.

Assuming the deflector I5 to be in the position indicated in Fig. 2 and, with the smoke coming from the right, at least a portion of the smoke within the breeching will pass into the housing I on the near side of the deflector and pass out of the housing on the opposite side thereof. It is therefore apparent thatthe density of the smoke contained at any given moment in the chamber II] will bear a substantially constant ratio to the condition of the entire body of smoke passing through the breeching.

Means are provided for continuously indicating 'the smoke content of the gases passing through the smbke chamber ill. In the present instance this means comprises an arrangement of parts adapted to convey to the eye of the attendant an indication by means of which he may be instantly informed concerning the relative density of the smoke passing through the smoke chamber. For this purpose a source of light is provided in the form of a lamp, the housing of which is indicated at 20, see Figs. 1 and 2. The light rays entering the opening 2I in the present instance, pass out of the chamber through a similar opening 22 in line with the opening 2I and located in the opposite wall of the housing I0. From the opening 22 the light rays from the lamp 20 are v directed into a mirror 23 arranged to deflect the smoke chamber.

While-varying forms of construction may be employed to substantially close the openings 2| and 22 in the housing I0, in the present instance each opening is preferably provided with an adjustable tube, these tubes being indicated at 24 and 25. For the purpose of slidably associating the tubes 25 and 25 with the housing II), sleeves 26 and 21 are formed at the respective openings mouth of the opening in the smoke chamber.

threaded part of the tube 25. Thus the glass may be removably secured on the end of the tube to permit the passage of light therethrough, but substantially closing the end of the tube from the entrance of air. For ordinary installations it has been found desirable to provide tube 25 with a translucent panel of ground or frosted glass or other suitable material and to fit the tube 2 3 with a transparent panel. Thus the light passing through the tube 25 to the mirror is diifused and softened, making for greater ease in observation.

Furthermore, when no mirror is used, so that the attendant views the translucent panel directly, it is unnecessary for him to take a position exactly-in front of the panel in order to obtain a reading of the condition of the interior of the smoke chamber.

In order to keep the panels 28 free from smoke, soot and the condensation of moisture thereon, one or more ventilated apertures 3I are provided in the tubes 26 and 25 which are controlled by an adjustable ring 32 having similar spaced apertures 33, 33 therein by means of which the apertures 3| may be opened or closed to a greater or less extent. The ring 32 may be formed similar to an ordinary hose clamp and is provided with extended portions through which a bolt 34 passes so that when the nut of the bolt is tightened thereon it will cause the ring to grip the tube with more or less friction so that the ring may be secured in any adjusted position. The purpose and function of the apertures 35 in the tubes 26 and 25 will be fully pointed out as the description proceeds.

The lamp 2!! and the mirror 23 are preferably associated with the housing It] so as to be carried thereby and thus form a unitary construction. For this purpose there is provided a bracket element 35 suitably secured to the under side of the housing It and bearing a laterally extending part or web 36 to which are attached the inner ends of a pair of carrying arms 37 and 38, see Fig. 1. The outer ends of the arms 37 and 3B are supported by means of braces 39 and 40, the in her ends of which are bolted at ti to a downwardly extending web 62 on bracket 35. The lamp housing 20 is carried by a base 46 which is secured near the outer end of arm 31. An adjustable connection, indicated at 45, is provided between the housing 20 and the base 34 to permit the lamp to be tilted in such a manner that its rays will enter tube 23 to the best advantage. The mirror support, in a similar manner, is pivotally adjustable on a base member 56 secured to the outer end of arm 38.

A pair of auxiliary supports 47 and 38 are arranged upon the arms 3! and 38 and are provided with guide, rings 49 and 50 in which the tubes 24 and 25 are slidably supported. Set screws are threaded into the rings i and 50 and extend therethrough to bear against the sur face of the tubes whereby the latter may be positively held in any adjusted position. 1

According to the description thus far, it is apparent that the light rays from the lamp will pass through tube 2fl;into and through the smoke chamber-and thence through tube either direct to the attendants eye or to his eye through the medium of the mirror 23.

The adjustability of the tubes 24 and 25 makes it possible to vary the distance over which the light rays will travel through the smoke in the smoke chamber. For practical purposes the tubes may be considered as relatively free from smoke or, atleast, the smoke will pass only a short distheends of the tubes nearer together, the thick- 7 ness of the smoke bodythrough which the light rays pass is substantially decreased.

The purpose of the apertures 3| will now be more fully described. When the smoke chamber i0 is properly connected to the smoke conduit or breeching of a furnace, the breeching being connected to the ordinary smoke stack, there will' be a certain negative pressure within the breeching caused by the natural flow ofhot gases up the stack. This negative pressure worn: course, extend to the interior of the smoke chamber and will cause outside air to flow into the smoke chamv ber through apertures 3! when they are in open position. This inflow of air insures that the tubes 24 and 25 will at all times be clear of smoke, especially between the apertures and the closed end or the tube. Thus, no opportunity is afforded for the smoke to approach the glass panel 28 withthe consequent lessening of its transparency.

It has been found that, in tubes of relatively small diameters running from flve or six inches on down to sizes considerably smaller, very effective results are obtained by spacing the air inlet apertures from the closed end of-the tube a dis-' standard units with a series of controlled aper tures extending longitudinally of the tube. For this purpose one or more additional rings-are provided as indicated at 22*, such rings controlling two or more circumferentially spaced apertures similar to aperture 3|. Y

An additional sight means, in the present instance, is provided for affording the attendant another view of the smoke sample illuminated by the light rays. For this purpose a sleeve 52 is formed in the housing in and is arranged with its opening in line with the light rays passing across the chamber between the openings 2| and 22 so that the smoke illuminated by such light rays may be viewed through this sleeve. An adjustable sight tube 53 is provided for the sleeve 'opening 52 and is adapted to be held'in fixed po- "previously described.

The arrangement'just described provides another veryimportant function, namely, to enable the attendant to quickly and thoroughly clear the entire smoke chamber. This is done by simply removing the ring and glass panel 55 thus opening the entire tube 53 for the ingress of outside air. In lieu of merely removing the ring and glassf the entire tube 53 maybe removed front opening 52. The immediate result of this operation, while smokeis being discharged through the breeching and up 2the"St8-Ck, is to entirely. displace all smoke in the trap'chamber with'clear outside air. I The attendant may thus be assured, while viewing the --light effect inthe mirror 23 or directly through tube 25, that he is receiving an absolute "zero or no smoke" indication. By again closing the sight opening the attendant will again promptly receive a smoke indication if there is smoke actually present in the furnace gases. Thus it is clear that a convenient check for zero reading is provided without in any manner adjusting or disturbing the combustion chamber conditions.

The modified form of the invention illustrated in Fig. 7 is intended for use when, for any reason, it may be undesirable to use a positive deflecting means'such as the deflecting plate l5; or it maybe used to assist the operation of the. defleeting plate in effectively introducing the furnace gases into the smoke chamber. In this form of the invention a suction tube 60, communicating with a suitable suction producing means, not shown, such as a draft producing fan, is con- .nected at its inner end to the housing of the smoke chamber lll' by means of a sleeve connection 6! formed in the housing. In order to regulatethesuction through the tube 60 to the proper amount for the best operation of the device, there is provided a damper valve 62. In other respects this modified 'form is constructed similarto the form of the invention first described.

It has been found desirable for certain installations to equip the indicating device with means by which an indication other than a mere light effect may be transmitted either electrically or mechanically to a position of maximum convenience to an attendant. For this purpose a light sensitive means or device, located in an open hood or casing 65 (see Fig. 8), is arranged to receive the rays of light passing from the smoke chamber through light tube 25a. The particular form of light sensitive means to be'used in this connection is immaterial insofar as the present invention is concerned. Any arrangement whereby variations in the intensity of the light impinging on the light sensitive means maybe continuously converted or transposed into mechanical or electrical eflects will serve the purpose. The casing 65 of the light sensitive means is preferably supported on a standard 46a located on an arm 38a all similar to the construction illustrated in Fig. 1. When the indicating device is equipped with light sensitive means the end of tube 251; is preferably closed with a transparent panel instead of a translucent panel as previously stated.

The use and operation of the device will now be described.

When itis desired to attach the indicator assembly to a smoke conduit such as the breeching of the furnace, a suitable opening is formed in the'breeching the openl'ngbeing preferably about equal in size and shape to the opening. ll in the chamber Hi. When a deflecting means such as the deflector "is to be employed, ,it' will next be 1 secured-with the portion l9 extendingangularly from the housing in a. direction oppositev to that in which the furnacugases flow through the breeching, so that the gases will be caused.to enter the smoke chamber asabove described. The housing I0 is next bolted inplace with the opening ll. aligned with the opening in the breeching so as to form a substantially. gas tight connection 5 u "H -1211';

After the dev1ce-has been attached. to the breeching and furnace gases conducted therethrough the lamp will be lighted to illuminate a portionof the interior of the smoke trap chamber thus makingread y Visible any, smoke passing through the chamber. 'The presence of smoke may be noted by looking directly into the tube .25 or by viewing the light passing from this-tube The illuminated through one, or more mirrors. smoke may also be viewed through tube 53 located in the end of the trap chamber. As above stated, the attendant may readily compare the'interior of the chamber when free of smoke with its appearance when smoke is passing through it by simply removing the panel closing the end of tube 53 thus permitting outside air to rush in due to the draft and clear the chamber or at least that portion normally illuminated by the lamp. 1

When it is desired to employ the light -sensi-- tive means 65 as a part of the indicating device, all of the major adjustments will .be ordinarily made before the device leaves the factory. After connection of the device to the breaching; certain additional slight adjustments may be necessary in order to adapt the device to the requirements of the particular furnace installation. Inmaking the final adjustments the operation of the indicating means, which is connected to the light sensitive cell, is carefully checked in conjunction with observations of the density of smoke passing through the area lighted by the lamp .20. When the person installing the device is assured that no smoke is passing through the trap chamber, as by opening tube 53, he next observes the instruments which are associated with the light sensitive cell, and if these instruments do not give a zero, or no smoke indication, he makes the necessary adjustments so that such an indication will be given. For convenience in making proper adjustments the base of the lamp 20 is preferably adapted for slidable movement toward and from the smoke chamber in suitable guides located on the arm 31; or the lamp itself may be mounted for horizontal adjustment withmodification of the instrumentalities combined with the light sensitive cell or may involve a change in the candle power of thelamp as by means of a variable resistance element connected therewith or by merely substituting for the lamp another lamp of different brightness.

After checking the zero point, the device may next be observed with varying densities of smoke to check the indications made under such condi tions. If the density of the smoke is not represented accurately by the indicating instruments one expedient for correcting the indication is the adjustment of the tubes 24 and 25 to bring their 1 endsat the proper distance from each other so i scription to indicate the scope of the invention.

that a body of smoke of the desired thickness may be obtained. The smoke will not enter the tubes to any considerable extent by reasonof the ventilating apertures therein, and, as these apertures are capable of variation, they too will, in some cases, be useful in the proper regulation of the thickness of the body of smoke through which the light rays pass. The ventilating openings thus not only serve to keep the glass at the ends of the tubes from becoming dirty, but also assist. in some cases at least, in the proper regulation of the thickness of the smoke body. After the indicating devices have been properly calibrated to suit the requirements of a particular job, they will require very little further attention. However, the operator may always confirm the indication given by the instruments by observing the amount of smoke in the smoke chamber throug the sight tube 53.

The operation of-the modified form. shown in Fig.7, isaubstantiallythesameaaintheilrlt form with the exception that an additional adjustment is possible by varying the angle of the damper valve 62 or in any other way varying the suction at the inlet end of the tube 60.

From the foregoing description it is apparent that the present invention provides a unitary device adapted for ready attachment to a smoke passage to afford an accurate indication of the A smoke content of the gases traveling through the passage. As the gases are caused to travel continuously through the device, it is possible to indicate accurately at any given instant the relative amount of smoke produced in the combustion chamber, and the instruments for effecting the indication can be brought into any convenient position. Where an electrical indicating device is associated with the light sensitive means, the device obviously may be located in any position convenient to the attendants charged with the responsibility of maintaining the combustion chamber in a smoke free condition. Dual instruments may also be provided at any other distant point. For example, at the station of an executive in charge of a battery of boilers. The device of the present invention can be made up in standard form, but at the same time it is adapted for a nice adjustment to suit the requirements of a particular power plant. One very important advantage which the present invention affords is that it is not necessary to project the light rays into or through the breaching proper. This consideration is of the utmost importance when the breeching is inaccessible except from one side.

, The device may be employed either with or without a mechanical deflector, and when the deflector is used it may be easily arranged in the proper position to deflect gases into the smoke chamber regardless of direction of travel of the smoke. In installations where the deflecting means is not used it will be obvious that a portion of the smoke is therefore desired that the present embodiment r be considered in all respects as illustrative and not restrictive, reference being had to the appended, claims rather than to the foregoing de- We claim v 1. A smoke indicating device comprising a housing forming a chamber substantially closed except on one side, means for readily attaching the open side of said housing to a smoke conduit, detachable deflecting means mounted on the housing and projecting into the interior of the conduit for causing at leasta portion of the smoke from the smoke conduit to enter into and pass through said housing back into said conduit. and a transparent panel located in the wall of said housing through which the interior of the smoke chamber may be viewed.

2. A smoke indicating device comprising in combination a smoke conduit having an opening I ing in register with the opening in said conduit,

means for causing a flow of at least a portion of the gases in said conduit into the housing and thence back into said conduit, and a transparent panel located in the outer end of said housing through which the interior of the housing may be viewed. r

3. A smoke indicating device comprising in combination a smoke conduit having an opening in the side thereof, a housing forming a smoke chamber, secured to said conduit and having a single opening therein registering with'the opening in said conduit, a deflecting plate located substantially centrally of said housing and' having a portion thereof extending into the housing and another portion extending into the conduit and biased in a direction opposite the direction of travel of the smoke whereby said deflector will cause a stream of smoke to enter the housing at one side of its opening and leave the housing at the other side, and means associated with said smoke chamberfor indicating the smoke content thereof. 7

4. A smoke indicating device comprising in combination, a smoke conduit having an opening therein extending laterally of the direction of the flow of gases therethrough, a unitary, substantially uniformly tapered housing forming asmoke chamber detachably secured directly to said conduit and having a single opening substantially as large of the greatest diameter of said chamber so as to facilitate the filling of the entire chamber with smoke, said opening registering with the opening in said smoke conduit, an auxiliary conduit connected to said chamber at a pointremote from the opening into the smoke conduit, means for causing a suction through said auxiliary conduit whereby a deflection of the gases from said smoke conduit into said housing is efiected, and means for indicating the relative concentration of smoke within the said chamber.

5. A smoke indicating device comprising a smoke conduit, a trap chamber associatedtherewith andadapted for the passage of smoke therethrough, a light inlet opening in said chamber 'the thickness of the body of smoke through which the light rays pass may be varied.

6. A smoke indicating device comprising a smoke conduit, a trap chamber associated therewith and adapted for the passage of smoke there- 3 through, a pair of spaced apart, aligned tubes extensible into the housing from opposite sides oi! said housing, a source of light arranged to direct light rays through one of said tubes into the chamber and through the other tube, means locatedat the remote end of said second tube adapted to be influenced by changes in the intensity of thelight impinging upon it whereby the concentration of the smoke in the trap chamber may be indicated, and means whereby the spacing of the inner ends of said'aligned tubes may be altered so as to vary the distance the light rays will pass through the chamber proper.

'7. A'smoke indicating device comprising a housing forming a smoke trap chamber adapted to be connected to a smoke conduit to receive at least a portion of the smoke normally passing through the conduit, aligned light inlet and outlet tubes located in said housing, a bracket mounted directly on said housing and independent of said tubes, arms carried directly by said bracket and extending outwardly of the housing, a lamp carried by one of said arms and disposed to direct light rays through said aligned light inlet openings, and a light sensitive means carried by the other of said arms and adapted to receive light rays from the lamp after the rays have passed across the smoke chamber through said aligned openings.

8. In a smoke indicating device a tapering boxlike housing forming substantially a closed chamber except at its large end which is provided with an opening substantially congruent with said end, means for readily attaching the open end of said housing directly to the side wall of a smoke conduit provided with a single-opening registering with the opening in said housing whereby a porconnected to'a smoke conduit to receive at least a portion of the smoke normally passing through the conduit, aligned light inlet and outlet openings in said housing, a bracket mounted directly on said housing, arms carried directly by said bracket and extending outwardly of the housing, a lamp carried by one of said arms and disposed to direct light rays through said aligned light inlet openings, a lightsensitive means carried by the other of said arms and adapted to receive light rays from the lamp after the rays have passed across the smoke chamber through said aligned openings, adjustable tubes adapted to extend into the housing to vary the effective thickness of the smoke body therein, and auxiliary guiding means mounted on said arms and support ing said tubes for sliding movement.

10. A smoke indicating device comprising in combination, a smoke conduit having a single opening therein extending laterally of the direction of flow of gases therethrough, a box-like housing comprising interconnected sidewalls of tapered, tubular form and an end wall closing the small end of the housing, the large end of said housing having an. opening substantially congruent with the interior of said housing and of such size as to substantially register with the opening in said conduit, means for readily attaching the large open end of said housing directly to the side wall of the smoke conduit with its opening in substantial registration with the opening in said conduit whereby a portion of the smoke and gases passing through the conduit will enter and fill substantially the entire chamber, and means associated with said housing for indicating the density of smoke therein.

11. A smoke-indicating device comprising in combination, a smoke conduit having a single opening thereinextending laterally of the direction of flow of gases therethrough, an elongated box-like housing having an opening at one end substantially congruent with the interior of said housing and of such size as to substantially register with the opening in said conduit, means forreadily attaching the open end of said housing directly to the side wall of the smoke conduit with its opening in substantial registration w at.

12. In a smoke indicating device the combine- 10 tion of as housing forming a. chamber substantially closed except on one side, means for readily attaching the open side or said housing to a smoke conduit, and deflecting means mounted on the housing and projecting into the interior of the conduit for causing at least a. portion of the smoke from the smoke conduit to enter into and pass through said housing back into the conduit.

THOMAS W. MGNEIIL. FREDERIC MCNEILL. 

